1. Field of the Invention
The present invention relates to a vertical type heat processing apparatus and a vertical type heating method.
2. Background Art
In the manufacture of semiconductor wafers, various processes including oxidation, film forming and the like, are provided to each semiconductor wafer (substrate), and, for example, a vertical type heat processing apparatus (or semiconductor manufacturing apparatus), in which multiple sheets of wafers can be processed in a batch-type manner, has been employed as an apparatus for performing such processes (e.g., see Patent Document 1 (TOKKYO No. 3378241, KOHO)). The vertical type heat processing apparatus includes a loading area (transfer area) below a vertical type heating furnace having a furnace port at a bottom portion. In the loading area, a boat (or substrate holding tool) is mounted on a cover adapted to open and close the furnace port, via a heat insulating mount. The boat serves to receive and hold, therein, multiple sheets (e.g., 100 to 150 sheets) of wafers each having a large size, for example, a 300 mm diameter. In addition, a lifting mechanism for carrying in and carrying out the boat relative to the heating furnace by raising and lowering the cover, and a loading mechanism for loading or transferring the wafers between the boat and a carrier (or container) containing the plurality of wafers therein are also provided in the loading area.
The boat is made from quartz, which is quite expensive. The wafers are also expensive, thus the production cost will be more increased with further progress of the processing steps. Accordingly, handling of these components or materials must be carried out with greater care.
However, in the batch-type semiconductor manufacturing apparatus described above, the construction of the apparatus poses various restrictions on the conditions for the software and hardware, as such making it difficult to render the apparatus better suited for an earthquake resistant construction or earthquake-proof function, thus being currently insufficient against earthquake problems. Therefore, when an earthquake occurs and the apparatus experiences a greater shake, fall down of the boat and serious breakdown of the boat and wafers may tend to be caused, leading to drastic damage.
To address these problems, in the vertical type heat processing apparatus described in the Patent Document 1 (TOKKYO No. 3378241, KOHO), a structure for connecting and fixing a bottom plate of the substrate holding tool and the heat insulating mount to each other by using a substrate holding tool fixing member is employed.
In the vertical type heat processing apparatuses, those employing the so-called two-boat system have been known. In each of such apparatuses, two boats are employed, such that while one of the boats is carried into the heating furnace and subjected to a heating process, the other boat can be used for loading semiconductor wafers therein.
However, in the vertical type heat processing apparatus employing such a two-boat system, the change of the boats on the heat insulating mount should make it difficult to employ the structure for connecting and fixing the substrate holding tool to the heat insulating mount by using the substrate holding tool fixing member. Thus, there is a risk that the boat on the heat insulating mount may take a fall when receiving an external force, such as an earthquake or the like. Meanwhile, as the type not including the heat insulating mount on the cover, those having a structure including a locking member capable of engaging and disengaging a mounting portion on the cover relative to the substrate holding tool due to rotation of the locking member and a rotating part for rotating the locking member have been proposed (see Patent Document 2 (TOKUKAI No. 2003-258063, KOHO)). However, such a structure requires the rotating part for rotating the locking member, in addition to a rotating mechanism for rotating the substrate holding tool, thus inevitably complicating the structure and rendering itself inapplicable to those including the heat insulating mount.